Thrombopoietin, polypeptide cytokine composed of 332 amino acids, activates the production of platelets by stimulating the differentiation and proliferation of megakaryocytes through the receptor and is expected as a medicine for hemopathy accompanied with the unusual number of platelets, for example, thrombocytopenia. DNA sequences encoding the thrombopoietin receptor have been described in Proc. Natl. Acad. Sci., 89, 5640–5644 (1992). Low molecular peptides having an affinity for the thrombopoietin receptor is also known (JP98/72492A and WO96/40750), but these peptide derivatives are not generally practical for oral administration.
1,4-Benzodiazepine derivatives as a low molecule compound having an affinity to the thrombopoietin receptor is described in JP99/1477A and JP99/152276A.
As the compound having a similar structure of the present invention compound, indoline derivatives having an anticholecystokinin actvity and an antigastrin activity are described in JP91/279374A, and benzothiazole derivatives are described without referring to its activity in Pharma Library Collection, Otava Chemical Collection and the like, but the affinity for thrombopoietin receptor is not described therein.